Method of treating asphalt



Patented Oct. 28, 1924.

UNITED STATES ANDREW J. ROWLAND, OF CINCINNATI, OHIO.

METHOD or TREATING ASPHALT.

No Drawing.

To all whom it may concern;

Be it known that I, ANDREW J. ROWLAND, a citizen of the United States,residing at Cincinnati, in the county of Hamilton and State 01" Ohio,have invented certain new and useful Improvements in Methods of TreatingAsphalt, of which the following is a specification.

My invention consists in the process of treating asphalt set forth andclaimed.

In carrying my invention into effect, I prefer to proceed substantiallyas follows:

A quantity of asphalt, either natural or petroleum, coal-tar pitch,bituminous products, or vegetable tars, is first subjected to heat forthe purpose of melting the same, whereby a liquid product is formed.This liquid product is then subjected, while at a temperature of about300 F., to the blow? ing of air therethrough for a period of from threeto twenty-four hours, depending upon thehardness desired in the finishedproduct. The longer the blowing continues the harder will be thefinished product. The purpose of air-blowing the product is to oxidizeit and give it a rubbery and elastic consistency, in order to render theproduct pliable so that it will readily bend instead of crack when thepaper is bent or if the container is subjected to a sudden shock orblow. Th product is air-blown without the addition of any metallic ororganic salts so that the finished product will contain no salts thatcan be acted upon by the acids. The asphalt may be air-blown withcatalyzers present and after the blowing is finished, washed to removethe catalyzers, or if the asphalt has already been air-blown it may bewashed to remove the metallic salts before completing it for use as acoating.

The crude asphalt or other equivalent product is then washed to removeany water soluble salts .that may be contained in it before it is incondition for the acid-proof, alkaliproof or waterroof purposes hereinsetforth. The was in consists in thoroughly agitatin it for a out thirtyminutes in a. boiling was solution composed of from A Application filedSeptember 30, 1920. Seriafl No. 413,776.

five to ten per cent of hydrochloric acid and from ninety to ninety-fiveper cent water, '56 after which the asphalt is boiled in clean wateruntil free from acid. After the washing is completed the asphalt is thenheated to about 300 F. in order to drive off any water that may be heldby entrainment in 56 the asphalt.

The resulting product when cold is a solid plastic mass which can bethinned with benzol or naphtha or any of the volatile organic solventsto any degree of consistency re- 60 quired for its use on paper orfabric containers, and on containers of wood, metal and the like.

For heavy coating about fifty per cent of asphalt and fifty per cent ofsolvent may be 5 used. If the article to be treated for the purpose ofrendering it acid-proof, alkaliproof and water-proof is dipped in theasphalt, no solvent is necessary,-but the asphalt is kept at atemperature of about 200 W F. to 220 F. and the articles to be treatedare simply dipped in the asphalt.

y main purpose is to produce a pliable acid-proof and alkali-proofcoating that is water-proof and acid-proof to all acids ex- II ceptconcentrated sulphuric acid, nitric acid and hydrochloric acid, and issuitable for any commercial strength of these acids.

Furthermore, while the claim has been drawn to specify asphalt, it willbe understood that the claim will include any equivalent material, suchas coal-tar pitch, bituminous products, vegetable-tars and the like.

Having described my invention and its manner of use, what I claim as newand de sire to secure by Letters Patent is:

The herein described process which consists in first heating the asphaltto a temperature of about 300 F., then blowing air therethrough at thattemperature for from three to twenty-four hours, then boiling theasphalt in dilute hydrochloric acid solution and then washing saidasphalt by boiling it in clear water and then heating said asphalt toabout 300 F.

ANDREW J. ROWLAND.

